In the art of article handling, various types of sorting devices have been provided heretofore. For example, switches have been provided for receiving articles from two or more input conveyors and for converging the articles, so that all articles are directed to a single output conveyor. Other switches have been designed to receive articles from a single input conveyor and to divert the articles so that the articles are selectively directed to one of two or more output conveyors. Still other sorting switches have operated to receive articles from a pair of input conveyors and to direct articles to a pair of corresponding output conveyors while selectively combining certain articles by directing them to a third output conveyor.
A number of devices have been developed which provide horizontal switching and sorting capabilities. Examples of such devices are the sorting switches disclosed and claimed in U.S. Pat. No. 3,986,596 issued Oct. 19, 1976 to D. R. Hamilton, U.S. Pat. No. 3,987,888 issued Oct. 26, 1976 to I. E. Wickam and U.S. Pat. No. 4,508,206 issued Apr. 2, 1985 to J. W. Moore. The foregoing patents, all of which are assigned to the Assignee hereof, disclose and claim sorting switches that constitute important contributions to the art of sorting switches and article handling. These switches are, however, primarily adapted to handle articles comprising integral units, such as boxes or tightly wrapped packages and are not particularly suitable for handling or sorting articles comprising loosely bound bundles of papers, letters or magazines.
Currently, the handling and sorting of loosely bound bundles of papers, letters and magazines is largely done by hand. For example, mail is delivered to post offices in sacks of loosely bound bundles of papers, letters and magazines. The bundles are removed from the sacks and manually delivered to individual work stations where the individual pieces are sorted. This process is labor intensive and time consuming. Heretofore the process of delivering the bundles of mail to the individual work stations has not been mechanized or automated due to the lack of a switch adapted to and suitable for sorting and switching loosely bound bundles of papers, letters and magazines.
The present invention comprises a novel sorting switch which fulfills the foregoing and other requirements long associated with the prior art. In accordance with the broader aspects of the invention, a plurality of pallets are mounted for sequential movement around a closed course incorporating an upper article sorting portion and a lower return portion. The upper sorting portion of the closed course comprises diverging article conveying paths. The diverging article conveying paths are defined by guide members, and the pallets may be selectively switched to travel along the article conveying paths defined by the guide members. The lower portion of the closed course comprises a return section wherein return guide members align the pallets along a central path corresponding to the location of a switching mechanism.
In accordance with the more specific aspects of the invention, a closed course is defined by a pair of parallel roller chains. Each pallet is slideably supported on a pair of parallel tubular pallet support members extending between and connected to the roller chains. Each pallet comprises an upper article bearing surface and arcuate lower side surfaces. Each pair of tubular pallet supports is positioned relative to the adjacent pairs of tubular pallet supports such that the sides of each pallet are maintained in substantially abutting relationship with the sides of each adjacent pallet as the pallets move through the closed course. Consequently, there are no gaps between the pallets through which a loose paper, letter or magazine might fall. Moreover, the arcuate lower side portions of the pallets allow the pallets to remain in constant contact as the pallets travel from the upper article sorting portion of the switch to the lower return portion.
Knife edge conveyors are used to load and unload bundles of loosely fastened papers, letters and magazines to and from the article sorting switch. The knife edge conveyors enable the sorting switch to be loaded and unloaded at substantially the same vertical elevation as the upper article sorting portion of the switch. Thus, loose bundles of papers, letters and magazines may be conveyed and switched without being subjected to any substantial vertical drops. The absence of any substantial vertical drops minimizes the number of bundles that are broken or fall apart and consequently reduces the amount of labor required to collect and rebundle loose pieces.
The present invention provides numerous advantages over the sorting switches of the prior art. The present invention provides a means of mechanizing the handling of loosely fastened bundles of papers, letters and magazines which, prior to the present invention, required the expenditure of significant labor. Another advantage of the present invention is the capability of switching and sorting loosely fastened bundles of papers, letters and magazines without subjecting the bundles to any substantial vertical drops, thereby minimizing the number of bundles broken, and the number of loose pieces requiring rebundling. Still another advantage of the present invention is the handling of articles comprising loosely bundled papers, letters and magazines in an economical manner heretofore unknown. These and other advantages deriving from the use of the invention will readily suggest themselves to those skilled in the art.